DataServiceContext 中的 AddLink 和 SetLink

发布于 2024-10-12 02:36:05 字数 741 浏览 6 评论 0原文

我是 ADO.NET 数据服务的新手。我只是想了解如何使用它。

我想设置两个现有对象 city 和comingCity 之间的链接：

IncomingCity 和 City 具有多对一关系：城市有房产 Collection IncomingCity IncomingCity 仅有一个相关的 City -- 属性是 City City

我所做的操作：

var entities = new referenceEntities(new Uri(url));

DataServiceQuery<IncomingCity> query = entities.IncomingCity.Expand("City");

var otherCities = query.Where(ic => ic.City == null);

var first = otherCities.FirstOrDefault();

entities.AddLink(originalCity, "IncomingCity", first);
entities.SetLink(first, "City", originalCity);

first.UpdatedAt = DateTime.Now;

entities.UpdateObject(first);

entities.SaveChanges();

在 SaveChanges 方法期间发生这样的异常：

处理此请求时发生错误。

我不明白怎么了。有人知道吗？

原文

I'm newby at ADO.NET Data Services. I'm just trying to understand how to work with it.

I'd like to set the link between two existing objects city and incomingCity:

IncomingCity and City has many-to-one relationship:
City has property Collection IncomingCity
IncomingCity has the only one related City -- the property is City City

The operations i do:

var entities = new referenceEntities(new Uri(url));

DataServiceQuery<IncomingCity> query = entities.IncomingCity.Expand("City");

var otherCities = query.Where(ic => ic.City == null);

var first = otherCities.FirstOrDefault();

entities.AddLink(originalCity, "IncomingCity", first);
entities.SetLink(first, "City", originalCity);

first.UpdatedAt = DateTime.Now;

entities.UpdateObject(first);

entities.SaveChanges();

Such an exception occurs during SaveChanges method:

An error occurred while processing this request.

I cound not understand what's the matter. Does anybody know?

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